Fluid-operated pumps, such as diaphragm pumps, are widely used particularly for pumping liquids, solutions, viscous materials, slurries, suspensions or flowable solids. The word "liquid" as used herein is intended to include all such materials. Typical diaphragm pumps of this general type are shown in U.S. Pat. Nos. 3,782,863, 4,131,397, 4,472,115, 4,624,628, and 4,895,494.
Double diaphragm pumps of the type disclosed in the above-listed patents are well known for their utility in pumping viscous or solids-laden liquids, as well as for pumping plain water or other liquids, and high or low viscosity solutions based on such liquids. Accordingly, such double diaphragm pumps have found extensive use in pumping out sumps, shafts, and pits, and generally in handling a great variety of slurries, sludges, and waste-laden liquids. Fluid driven diaphragm pumps offer certain further advantages in convenience, effectiveness, portability, and safety. Double diaphragm pumps are rugged and compact and, to gain maximum flexibility, are often served by a single intake line and deliver liquid through a short manifold to a single discharge line.
In such pumping apparatus, a diaphragm forming a movable wall of a pumping chamber is moved in a suction stroke to draw liquid into the pumping chamber. The diaphragm is then moved in the opposite direction in a pumping stroke to force the liquid out of the pumping chamber by pressurized drive fluid acting directly on the diaphragm.
In double diaphragm pumps in which two diaphragms are connected together, each diaphragm has, on one side, a pumping chamber and, on the other side, a drive fluid chamber. Air or other fluid under pressure is alternately introduced into and exhausted from each drive fluid chamber. A control valve directs the fluid under pressure into one drive fluid chamber, causing the associated diaphragm to move in a pumping stroke, while the connecting mechanism pulls the other diaphragm in a suction stroke and causes air in its associated drive fluid chamber to be exhausted. Then air under pressure is introduced into the other drive fluid chamber to move its diaphragm in a pumping stroke.
Double diaphragm pumps have conventionally used a connecting rod extending coaxially between the two diaphragms. In such arrangements, the drive fluid chambers of each pump section are adjacent to one another, and the pumping sections are spaced outwardly relative to one another. These known pumps, are costly to manufacture, and relatively difficult to disassemble for repair or maintenance. As a result, increased downtime is required for repair or maintenance, significantly increasing the operation costs of the pump system.